Vitamin B12

Methylcobalamin

Prepared by the ezGLP team. Sources last checked September 5, 2026.

Also known as Mecobalamin, Methyl-B12

Routes represented in the knowledgebase: Oral / Sublingual / Subcutaneous (SubQ).

Educational overview

Common as an oral supplement; no FDA-approved methylcobalamin injection was identified, so injectable forms are generally compounded or unapproved.

Category: Vitamin B12
Routes represented: Oral / Sublingual / Subcutaneous (SubQ)
Storage context: Follow the product or pharmacy label; requirements vary by route and formulation.

Authoritative overview

Published literature

No validated PubMed or DOI link is currently curated for this entry.

Safety evidence

Common or reported: injection-site reaction, rash or itching, mild diarrhea.

Serious or important: rare anaphylaxis, hypokalemia during rapid correction of severe deficiency.

Effects vary substantially by chemical form and route.

Safety evidence source

Interaction evidence

These are general, pairwise evidence notes. Green identifies the potential-synergy category, while Lv3/Lv2/Lv1 communicates evidence strength; it does not guarantee benefit or cancel a safety warning.

With metformin

Safety flag

Long-term metformin use can reduce vitamin B12 absorption and serum B12 concentration.

Interaction evidence source

Summarised from published literature for reference only, with citations to the source. Evidence is graded as reported and is not a recommendation to combine, dose, or use any compound.

For personal tracking and education only. Not medical advice, diagnosis, or treatment, and not a medical device. Peptides may be prescription-only or unapproved where you live — consult a licensed healthcare professional.